"""
REST API Generator (Placeholder)

This is a placeholder module demonstrating the extensibility of the MAQET
generator system. It shows how new API interfaces can be added to the
unified API framework.

Future Implementation:
    This generator would automatically create REST API endpoints from
    @api_method decorated methods, similar to how CLIGenerator creates
    CLI commands. The implementation would:

    1. Generate Flask/FastAPI routes from method metadata
    2. Convert method parameters to request parameters (query/body)
    3. Handle JSON serialization of return values
    4. Provide OpenAPI/Swagger documentation
    5. Implement proper HTTP status codes and error handling

Example Usage (when implemented):
    from maqet.generators.rest_generator import RestAPIGenerator
    from maqet.api import API_REGISTRY

    generator = RestAPIGenerator(maqet_instance, API_REGISTRY)
    app = generator.generate()  # Returns Flask/FastAPI app
    generator.run()  # Starts REST API server

    This would enable HTTP access to MAQET methods:
    POST /api/start?vm_id=myvm&detach=true
    GET /api/status?vm_id=myvm
    POST /api/qmp?vm_id=myvm&command=system_powerdown

Design Pattern:
    This follows the same pattern as CLIGenerator:
    - Inherit from BaseGenerator for common utilities
    - Implement generate() to create the API interface
    - Implement run() to start the server
    - Use API_REGISTRY.get_all_methods() to introspect methods
    - Leverage method metadata (parameters, types, descriptions)
"""

from typing import Any

from .base_generator import BaseGenerator


class RestAPIGenerator(BaseGenerator):
    """
    REST API generator placeholder demonstrating extensibility.

    This class serves as a demonstration of how new generator types
    can be added to the MAQET unified API system. When implemented,
    it would generate REST API endpoints from @api_method decorators.

    The implementation would follow the same pattern as CLIGenerator:
    1. Use self.registry to get method metadata
    2. Generate appropriate interface (REST routes vs CLI commands)
    3. Handle parameter conversion and validation
    4. Execute methods and return results in appropriate format

    Attributes:
        maqet_instance: Instance of Maqet class
        registry: API registry containing method metadata
    """

    def generate(self) -> Any:
        """
        Generate REST API interface from registered methods.

        When implemented, this method would:
        - Create a Flask/FastAPI application
        - Generate routes for each @api_method
        - Set up request parameter parsing
        - Configure JSON serialization
        - Add OpenAPI documentation

        Returns:
            REST API application object (Flask/FastAPI app)

        Raises:
            NotImplementedError: This is a placeholder for future implementation
        """
        raise NotImplementedError(
            "REST API generator is a placeholder demonstrating extensibility. "
            "To implement, create Flask/FastAPI routes from self.registry.get_all_methods() "
            "following the pattern in CLIGenerator. See module docstring for details."
        )

    def run(self, host: str = "127.0.0.1", port: int = 8000) -> Any:
        """
        Start REST API server.

        When implemented, this method would:
        - Call generate() to create the API application
        - Start the web server on specified host/port
        - Handle graceful shutdown and error recovery

        Args:
            host: Host address to bind to (default: 127.0.0.1)
            port: Port to listen on (default: 8000)

        Returns:
            Server instance or None

        Raises:
            NotImplementedError: This is a placeholder for future implementation
        """
        raise NotImplementedError(
            "REST API server is not yet implemented. "
            "This would start a Flask/FastAPI server on {host}:{port} "
            "with routes generated from @api_method decorators."
        )
